The Ninja Librarians Series

The Ninja Librarians Series
The Accidental Keyhand
By Jen Swann Downey

I was browsing through my local library and saw this and thought it was cute. I haven't read it, but maybe you could and tell me how you like it! Perfect for middle grades!

Goodreads summary:
"Just a little story about your average sword-swinging, karate-chopping, crime-fighting ninja librarians

Dorrie Barnes had no idea an overdue library book would change her life. When Dorrie and her brother Marcus chase her pet mongoose into the janitor's closet of their local library, they accidentally fall through a passage into Petrarch's Library -the headquarters of a secret society of ninja librarians who have an important mission: protect those whose words have gotten them into trouble. Anywhere in the world and at any time in history.

Dorrie would love nothing more than to join the society. But when a traitor surfaces, she and her friends are the prime suspects. Can they clear their names before the only passage back to the twenty-first century closes forever?"

Don't forget book #2 - Sword in the Stacks!